How to Fix Boot Issues on a Mac
Introduction
Boot issues happen when your computer will not power on, or you hear beeping when you power on the device. This guide will cover some troubleshooting steps to help you with these issues.
1 Boot POST Errors
When you turn on the computer it will perform some tests before it loads the operating system. If you hear beeping when you turn on your computer you likely have a hardware issue.
| Beeps | Issue | Service Required |
| None | This happens either due to no power to the system and your battery is dead. There is some situations you may be able to reset the NVRAM or SMC to resolve the issue. | Maybe |
| One | This happens when your computer doesn't detect any RAM in your computer. | Yes |
| Two | This usually happens when you install the wrong type of RAM in your computer. If you attempted a RAM upgrade on your own or at a repair center, it may not have the right type of ram installed. | Yes |
| Three | This usually happens when RAM isn't seated well into your computer or you have a bad / faulty stick of RAM in the computer. | Yes |
| Four | The system is unable to find a boot image. This can be indication of a faulty or corrupt hard drive. If you have your macOS install media, you may be able to boot to that media and repair your disk. | Maybe |
| Five | Usually when you get this code, your computer is having issues communicating between the CPU and the motherboard. | Yes |
? How many beeps did your computer make?
Boot issues happen when your computer will not power on, or you hear beeping when you power on the device. This guide will cover some troubleshooting steps to help you with these issues.
When you turn on the computer it will perform some tests before it loads the operating system. If you hear beeping when you turn on your computer you likely have a hardware issue.
| Beeps | Issue | Service Required |
| None | This happens either due to no power to the system and your battery is dead. There is some situations you may be able to reset the NVRAM or SMC to resolve the issue. | Maybe |
| One | This happens when your computer doesn't detect any RAM in your computer. | Yes |
| Two | This usually happens when you install the wrong type of RAM in your computer. If you attempted a RAM upgrade on your own or at a repair center, it may not have the right type of ram installed. | Yes |
| Three | This usually happens when RAM isn't seated well into your computer or you have a bad / faulty stick of RAM in the computer. | Yes |
| Four | The system is unable to find a boot image. This can be indication of a faulty or corrupt hard drive. If you have your macOS install media, you may be able to boot to that media and repair your disk. | Maybe |
| Five | Usually when you get this code, your computer is having issues communicating between the CPU and the motherboard. | Yes |
There are two ways to power up a MacBook:
- Using the power supply without the extension cord:
- Examine the cable and connectors for visible damage. If they are damaged, they may need to be replaced.
- Make sure the power supply is firmly plugged into the power socket and power connector into the computer.
- Using the power supply with the extension cord:
- Examine all cables and connectors for visible damage. If they are damaged, they may need to be replaced.
- Make sure the power supply is firmly plugged into the power socket, the extension cord into the power supply and power connector into the computer.
- The power adapter shapes and way of connecting them have stayed the same over the years, however the connector types that plug into the computer have changed somewhat and can be of the following types:
- Magnetic T style
- Magnetic L style
- USB-C style
If you computer will not respond to any input and appears frozen, press and hold on the Power button until the computer shuts off.
The power button on a Macbook is typically located on or near the keyboard while the power button on a Mac Pro will vary depending on the model.
Any unsaved work will be lost.
NVRAM (nonvolatile random-access memory) is a cache of settings specific to your Mac. Resetting NVRAM is safe, however you will need to reset some of your minor customizations, such as volume, time zone, or screen resolution.
- Turn your Mac on by pushing the Power button.
- Immediately push and hold the option, command ⌘, P, and R keys on your keyboard.
- If your Mac plays a startup sound, release the keys after the second time it plays.
- If there is no startup sound, release the keys after the second time the Apple logo disappears.
If you computer will not respond to any input and appears frozen, press and hold on the Power button until the computer shuts off.
The power button on a Macbook is typically located on or near the keyboard while the power button on a Mac Pro will vary depending on the model.
Any unsaved work will be lost.
Desktop
- Unplug the power cable.
- Press and hold the power button for 5 seconds.
- Plug in the power cable.
- Power the machine back on.
Laptop with Removable Battery
- Unplug the power adapter.
- Remove the battery.
- Press and hold the power button for 5 seconds.
- Replace the battery.
- Plug in the power adapter.
- Power the machine back on
Laptop without Removable Battery
- Plug in the power adapter.
- Using the built in keyboard, press the left Option, Control, and Shift and then press the Power button.
- Release the keys at the same time.
- Power the machine back on.
If your computer does power on to the Apple logo with a progress bar but does not fully load into the operating system, click the link below for some additional troubleshooting.
Clicking this button will open a new guide that will provide you with steps to resolve your issue.
If you are not getting a loading screen you will need to contact Apple for further assistance.
If you do not have the recovery / install media on USB media or DVD, contact Apple for options of obtaining media
- Insert the macos recovery / install media into your computer.
- Power on the computer and press the Option key down.
- Choose the macOS recover / install media that you inserted.
If your computer does power on to the Apple logo with a progress bar but does not fully load into the operating system, click the link below for some additional troubleshooting.
Clicking this button will open a new guide that will provide you with steps to resolve your issue.
If you are not getting a loading screen you will need to contact Apple for further assistance.